Selective pneumatic and gravity discharge car hopper construction



Aug. 23, 1960 G. B. DOREY 2,950,144

SELECTIVE PNEUMATIC AND GRAVITY DISCHARGE CAR HOPPER coNsTRUCTIoN 5 Sheets-Sheet l Filed Aug. 18, 1958 INVENTOR. @gorge Z5. o/y, BY

Aug. 23, 1960 G. B. DOREY SELECTIVE PNEUMATIC AND GRAVITY DISCHARGE CAR HCPPER CCNSTRUCTICN 5 Sheets-Sheet 2 Filed Aug. 18, 1958 INVENTOR.

Aug. 23, 1960 G. B. Dom-:Y

sELEcTvs PNEUMATIC AND GRAVITY DISCHARGE; CAR HOPPER coNsTRucTIoN 5 Sheets-Sheet 3 Filed Aug. 18, 1958 INVENTOR. Geo/@a 7a/gy BY ug. 23, 1960 G, B, DOREY SELEGTIVE PNEUMATIC AND GRAVITY DISCHARGE CAR HOPPER CONSTRUCTION 5 Sheets-Sheet 4 Filed Aug. 18, 195s INVENTOR. @e0/965 Barg, BY

5 Sheefcs-Sheet 5 Aug. 23, 1960 G. B. DOREY v SELECTIVE PNEUMATIC AND GRAVITY DISCHARGE CAR HOPPER CONSTRUCTION v Filed Aug. 18, 1958 INV ENTOR. 660g@ 5 Der@ Y United States Patent @mee 2,950,144 Patented Aug. 23, 1960 SELECTIVE PNEUNIAI'IC AND GRAVITY DIS- CHARGE CAR HOPPER CONSTRUCTION George B. Dorey, Westmount, Quebec, Canada, assigner to Enterprise Railway Equipment Company, Chicago lil., a corporation of Illinois rind Aug. 1s, 195s, ser. No. 755,503

11 claims. (ci. 3oz-s2) This invention relates to an improved selective pneumatic and gravity discharge car such as employed in railway hopper car construction and the like for conveying nely comminuted lading which may be discharged from the car either by suction or by gravity. The invention disclosed herein is an improvement over the construction disclosed in application Serial No. 723,329, filed March 24, 195 8, and assigned to the assignee of this application.

ln railway hopper cars of the type above referred tol and disclosed in the above application it has been proposed that a hopper be employed which is provided with a sliding gate at the bottom for closing the discharge opening, thereby providing a at bottom iloor with a conduit system in the form of a hollow ridge shaped partition disposed midway of and above the flat iloor for withdrawing lading therethrough and providing a discharge area at each side of the ridge shaped partition for gravity discharge when the gate is opened. With that system there generally remains after pneumatic unloading a residue of lading on those parts of the at floor portions which are most remote from the ridge shapedV partition. It is one of the main objects of this invention to avoid leaving any portion of the lading after the car has been unloaded pneumatically by providing sloping oors for directing lading toward the ridge shaped partition where it can be readily picked up pneumatically.

Other objects of this invention are: To provide closure means for a discharge opening incorporating oppositely swinging pivotally mounted doors to permit discharge of lading within a confining frame; to provide a pair of oppositely swinging doors for directing lading to a pneumatic conduit system when the doors are closed; to provide improved mechanism for operating the doors, the mechanism being contained within a coniining enclosure; and to provide an improved pneumatic conduit system for withdrawing lading from the car.

The invention also resides in certain details of construction associated with the improvement such as will be pointed out hereinafter and claimed.

For further comprehension of the invention, reference can be had to the accompanying drawings wherein the improvement is shown as applied to a railway hopper car.

ln said drawings:

Figure 1 is a vertical elevational view taken transversely through the lower part of a hopper showing the improvement applied thereto, said view showing approximately one-half the width of the car with parts thereof in section and showing the parts of the hopper positioned with the gravity discharge doors in closed position;

Figure 2 is a side elevational view of the structure shown in Figure 1 as viewed from left to right;

Figure 3 is a top plan view of Figure 2 with the upper hopper floor sheets eliminated and certain parts broken away to better illustrate the construction;

Figure 4 is a vertical transverse sectional view taken through the hopper frame and generally on a line 4 4 of Figure 3;

Figure 5 is a view, similar to Figure 4, except that the doors are shown in opened position and a removable extension chute is shown by conventional dot and dash lines;

Figure 6 is a vertical sectional View taken generally on a line 6 6 of Figure 2 with the gravity discharge doors shown in partially closed position; and

Figure 7 is a vertical fractional sectional view taken on a line 7-7 of Figure 2.

Referring now particularly toV Figures 1 and 2 of the drawings, it will be observed that the reference character 16 designates a part of a center sill of a railway hopper car which is located midway of the side walls one of which is indicated at 11. Between the center sill 10 and the car side wall 11 there is a load containing hopper that is indicated, generally, at 12. It will be understood that a similar hopper is located on the other side of the center sill 1i) and that two or more pairs of hoppers are provided for each car as may be desired. Since the construction of the hoppers is the same, except for opposite hand construction, a description of one will suice for all of them.

The load containing hopper 12 is formed by oppositely sloping floors 13 and 14 and `inner and outer side walls 15 and 16. The iioors 13 and 14 and side walls 15 and 16 are joined together along their juxtaposed edges and at the lower portion thereof they define a discharge opening that is indicated, generally, at 17.

Below the discharge opening 17 and secured to the lower margins of the sloping oors 13 and 14 and the side walls 15 and 16 is a sub-hopperas indicated, generally, at 1S. The sub-hopper 18 comprises generally a four sided frame and includes end walls 19 and 2li that overlie and are secured to the lower margins of the sloping iloors 13 and 14. The sub-hopper 18 also includes inner and outer side walls 21 and 22 which overlie the lower margins of the inner and outer side walls 15 and 16. lt will be understood that the end walls 19 and 20 and inner and outer side walls 21 and 22 of the sub-hopper 13 can be secured by welding or riveting to the lower margins of the sloping oors 13 and 14 and inner and outer side walls 15 and 16. As shown more clearly in Figures 4 and 5 of the drawings the inner and outer side walls 21 and 22 include downturned ange portions 23 and 24 which overlie the lower margins of the inner and outer side walls 15 and 16.

The inner and outer side walls 21 and 22 of the subhopper 18 include inwardly olset portions 21-21 and 2222' the lower portions of which merge with lower portions 19 and 20 of the end walls 19 and 2i). Extending through the offset portions 21-21' and 22'-22 are bolts 25 on which hinges 26 pivot. The hinges 26 are secured to doors 27 which cooperate with an inner shell or Iloor 28 that forms the bottom of a conduit, shown generally at 29, which extends between the end walls 19 and 20 of the sub-hopper 18. Openings 30 are provided on opposite sides of the conduit 29 and they are arranged, as shown in Figure 4, to be closed by the doors 27. As will appear hereinafter, when the doors 27 are closed, the lading in the sub-hopper 18 can be removed pneumatically. By opening the doors 27, the lading in the sub-hopper 18 can be discharged downwardly through the openings 30 by gravity all within the four sided frame which constitutes the sub-hopper 18. It will be observed that the inner and outer side Walls 21 and 22 are provided with triangular shaped sidewall sections 31-31 and 32-32. This is shown more clearly in Figure 3 of the drawings. Flanges 33--33 and 34-34 extend outwardly toward the doors 30 fromtherespective triangular shaped side wall sections 31-31 and 32432. VThe edges 35 and 36 of the flanges 33-33 and 34--34 engage the shown in Figure 4.

' 38 thereof are curved downwardly so that the outermost edges 39 and 40 thereof ,arev Vengaged by the inner surfacesl ofthe'resp'ectiveY door`27when closed, as shown in'Figure 4: I

' Now it will be apparent that the cross section ofthe sub-hopper 18 provides ar generally W-shaped hopper or two V-shaped hoppers are formed with the outer side walls being providedV by the doorsV 27--27 and the triangular shaped portions 31-31 and 32-32 of the inner and outer side Walls 21 and 22 while the inner sides are provided, in part, by theY conduit 29 and, in part, by the lowermost portions of the side portions 37 and 38 of the inner shell or oor28. Y

As pointed out hereinbefore the conduit 29 extends between the end walls 19 and 20.V It includes an inverted V-shaped hood or ridge shaped member 41 and,

Vwith theV inner shell or floor 28 it encloses a space or plenum 42 through which air is drawn, as will be set forth hereafter, for entraining'lading from opposite It is desirable that means be provided within the frame forming the sub-hopper 18 for conjointly operating the doors 27 from and to the closed position shown in Figure 4. For this purpose a shaft 69 is journaled at its ends in bearings 70 which are mounted on the lower portions 19 and 20 of the end walls 19 and 20. This construction is shown more clearly in Figure 2 of the drawings. The connectionsto the shaftr 69 appear more sidesof the inverted V-'shaped hood or ridge shapedV member 41 and discharging it out of the other end. The inverted' V-shaped hood or ridge shaped member 41 includes downwardly' sloping sides 43 and 44 whichextend toward the doors 27 and form the Yprincipal part of the inner walls of the W-shaped hopper. The lower edges 45 and 46 of the downwardly sloping sides 43 and 44 are spaced from the doors 27 in closed position, as shown in Figure 4, and also from .the margins of the side portions 37 and 38 of the `inner shell or iloor 28. This spacing is suc-h as to provide passageways 47 and 48 from the apices of the two V-shaped hoppers into the space or plenum 42 of the conduit 29. In order to insure a good seal for the openings 30 by the doors 27, the doors'27 are provided with side anges 49-49 which overlie the anges 33-33 and 34-34 on the triangular shaped side wall sections 31-31 and 32-32. Each door 27 is provided with lan upturned bottom flange 50 which underlies the margins of the side portions 37 and 38 of the inner shell or floor 28. In order to provide a relatively tight seal between the upper edges of the doors 27 and the under sides of the downturned flange portions 23Y and 24, the upper edges 51 of the doors 27 are curved and have sliding engagement with the lower margins of downturned ange Yportions 23 and 24 during the movement of the doors 27 between the closed position sho-wn in Figure 4 'and the open position shown in Figure 5.

fIn order to provide for the entrance of air into the space or plenum 42 an opening 53 is located in the end clearly in Figures 4 and 5 of the drawings. It will be observed that crank arms 71 and 72 are secured to rotate with the operating shaft 69and that at their outer ends they are pivoted at73and 74 to links 75and 76. At their outer ends the links 75 and 76 are pivotally connected at` 77 Vand 78 to lugs 79` whichl extend from the doors 27 below the bottom flanges 50 thereof. YThe ends of the links 75" and 76 areV adjustably connected to the lugs V'79 on-the doors 27 by eye bolts 80. The intermediate portions of the links 75 and 76 are indented as indicated at 81 and 82V in order that the linkage can fold over the operating shaft 69 as shown in Figure 4. In the folded position of the Ylinkage shown in this ligure with the doors 27 closed, the linkage is in a toggle locked position. This will be apparent since a line 83 joining the pivot 73 to the pivot 77 is located below the longitudinal axis of rotation ofthe operating shaft 69. Likewise, a line 84 extending betweenrthe pivot 74 and the pivot 78 is located slightly below this longitudinal axis. Thus, when the linkage occupies the position shown in Figure 4 of the drawings, the doors 27 are held closed.

In order tovrotate the operating shaft 69 a two part operating head, shown generally at 85 in Figure 2, is provided. Y It will be noted that the operating head 85 is located exteriorly Vof the four sided frame which forms the sub-hopper 18. The two parts for the operating head Y 85 are provided to permit application thereto Yof. an operating bar for rotating the shaft 69 in one direction to close the doors 27 and in the opposite direction to open them.

' For closing the doors 27 the two part operating head 85 includes fingers 86, Figure l, having pockets 87 therebetween. It will be observed that the outer ends of the fingers 86 are curved in a direction opposite to that in which the operating shaft 69 is rotated for closing the doors 27. The purpose of this construction will be apparentpresently. The other part of the two part operating head 85 is formed by lingers 88, Figure 6, which are located on opposite `sides of pockets 89. Here it will be observed that the. outerends of the lingers 88 are curved in a direction opposite to the direction in which wall 20. Communicating with the opening 53 is an air Y inlet conduit 54, Figure 2, the outer end of which is arranged to 4be closed by a gate 55. T'he gate 55 acts as a damper for controlling the amount of air that flows v through the air inlet conduit'54. The gate 55 is pivoted at 56 on the under side of the air inlet conduit 54 and it is held in any position to which it may be movedrby friction springs 57 which, as shown more clearly in Figure 3, bear against the side wallsY of the air inlet con-V duit 54'and hold the gate 55 in the position to which it has been adjusted. For holding the gate 55 in the fully closed position a latch 58 is provided. Itis pivoted at 59` to the top of the air inlet conduit 54.

The lading entrained in air flowing through vthe conduit 29Ypasses-out of the sub-hopper 18 through an openingf61 in the end wall 19. Arconduit extension 62 is connected to the end wall 19 and registers with the opening 61. At its outer end the conduit extension' 62 has a circularl end 63 that isarranged to be connected to a suitable source of suction (not shown). A cap 64 ts over the circular end63 of the conduit extension 62.

the shaft 69 is rotated to close the doors 27.

In order to hold the doors 27 in the closed position shown in Figure 4 in addition to the toggle operation of the linkage a locking dog 90 is provided. As shown in Figure 7, the locking dog 90 is pivoted at 91 on the lower portion 19 of the end Wall 19 for engaging a lug 92 that is formed integrally with a cam 93'which is fastened to the operating shaft 69.

Assuming that the doors 27 are in the Yopen position shown in Figure 6'and it is desired to close them', an 0perating bar 94 is positioned in the lowerrnost pocket 89 between an-adjacent pairV of ngers 88. Then the operating bar 94 is moved downwardly to rotate the operating shaft '69 in a counterclockwise direction. After the operating shaft 69 has been rotated a slight amount in this direction, another operating bar 95, shown by dot and dash lines, is inserted in the next pocket and the operating force isvtransferredY to it. The first operating bar 94 is removed and, as the closingoperation proceeds,'it is Y placed in the next pocket 89. The operationY continues Cams 65 extend radially from the cap 64 and wedgingly Y cooperate withcam sockets 66 provided onV the circular extension 62 for wedging the cap 64 in the closed position.

operating bar 94, as shown in Figure l, is positionedin c the left hand pocket 87 andrforce is applied to the outer end in a direction to rotate the operating shaft 69 in a clockwise direction. Only a slight rotation is required to move the links 75 and 76 from the toggle locked positions, shown in Figure 4, to the overcenter positions where the lading acting downwardly on the doors 27 causes them to swing downwardly and permit the lading to be discharged through the openings 30 on opposite sides of the conduit 29. It will be apparent now that, by providing the outer ends of the ngers 86 and 88 curved in the directions opposite to which the operating shaft 69 is to be rotated by the insertion of an operating bar in the pockets formed thereby, it is possible to hold the operating bar in position without slipping. At the same time, should the operating shaft 69 tend to travel faster than it is moved by the operating bar, the latter is thrown out of the pocket in which it may be located, thus avoiding any injury to the operator.

In order to provide for gravity unloading when the doors 27 and 28 are opened, provision is made for attaching a removable chute to the lower portion of the subhopper 18. For this purpose, as shown more clearly in Figures 4 and 5 of the drawings, a groove 97 is provided along the lower margin of the inner side wall 21 and an outwardly extending flange 98 is provided along the lower margin of the side wall 22. In addition a groove 99, Figure 2, is provided along the lower margin of the lower portion 19' of the end wall 19 and an outwardly extending flange 100 is provided along the lower margin of the lower portion 20 of the end wall 20.

Referring again to Figure 5 of the drawings it will be observed that a removable chute 101, shown by conventional dot and dash lines, has a peripheral ange 102 portions of which extend into the grooves 97 and 99 and other portions of which underlie the flanges 98 and 100 to which these portions can be secured by clamps one of which is indicated at 103 and also shown by conventional dot and dash lines.

With the arrangement described hereinbefore of the conduit 29 and the doors 27 it will be obvious that a car can be loaded at the loading station without previous knowledge as to the manner of unloading. Should pneumatic unloading be indicated upon arrival at the destination, the doors 27 remain in the closed position. The cap 64 is removed and a suction connection is made thereto. The gate 55 on the air inlet conduit 54 is opened to the desired amount and the lading is caused to ow through the passageways 47 and 48 from the apices of the two V-shaped hoppers into the space or plenum 42 within the conduit 29 and thence out of the conduit extension 62. The rate of unloading under these conditions depends upon the degree of vacuum that can be maintained and the opening of the gate 55. Since the downwardly and inwardly sloping inner faces of the doors 27 extend to the margins of the side portions 37 and 38 of the inner sill or floor 28, it is possible to remove all of the lading s o that no residue is left.

Should gravity unloading be indicated upon arrival of the car itis a simple matter to apply the removable chute 101, Figure 5. Then the locking dog 90 is swung away from the lug 92 to an overbalanced released position as shown in yFigure 6. Then, as shown in Figure l, a removable bar 94 is placed in the left hand pocket 87 and, by an upward movement of the outer end, the Vlinks 75 and 76 are moved past the toggle locked positions, shown in Figure 4, in the manner hereinbefore described and the doors 27 continue to Vmove to the open position shown in Figure 5 by the force of the lading acting downwardly thereon.

After the lading has been removed entirely from the sub-hopper 18 through the removable chute 101, the latter is removed and the doors 27 are closed in the manner described herei-nbefore using the two operating bars 94 and 95.

Since certain changes can be made in the foregoing construction and different embodiments of the invention can be made without departing from the spirit and scope thereof, it will be understood that all matter shown in the accompanying drawings and described hereinbefore shall be interpreted as illustrative and not in a limiting sense.

What is claimed as new is:

l. A pneumatically unloadable hopper structure for a. railway car or the like comprising, in combination, a fourwalled enclosure having downwardly and inwardly sloping spaced apart side walls joined by spacedapart end walls, a floor extending between said end walls and forming the bottom of a conduit the upper portion of which is formed by an inverted V-shaped hood the sides of which with the respective side walls form a pair of V-shaped hoppers with openings at the apex between each V-shaped hopper and the interior of said conduit, each of said side walls having an opening for the discharge of lading therethrough by gravity, a door closing each last named opening movably mounted on said enclosure, means providing an air inlet opening to said conduit, yand means providing an air and lading exhaust opening from said conduit.

2. A pneumatically unloadable hopper structure for a railway ca r or the like comprising, in combination, a four-walled enclosure having downwardly and inwardly sloping spaced apart side walls joined by spaced apart end walls, a floor extending between said end walls and forming the bottom of a conduit the upper portion of which is formed by an'inverted V-shaped hood the sides of which with the respective side walls form a pair of V-shaped hoppers with openings at the apex between each V-shaped hopper and the interior of said conduit, each of said side walls having an opening for the discharge of lading therethrough by gravity, a door hinged to said enclosure adjacent the upper side of each last mentioned opening to occupy an inclined position for closing such opening and swingable downwardly to an open position, means providing an air inlet opening to said conduit, and means providing an air and lading exhaust opening from said conduit.

3. A pneumatically unloadable hopper structure for a railway car or the like comprising, in combination, a four-walled enclosure having downwardly and inwardly sloping spaced apart end walls, a floor extending between said end walls and forming the bottom of a conduit the upper portion of which is formed by an inverted V- shaped hood the sides of which with the respective side walls form a pair of V-shaped hoppers with openings at the apex between each V-shaped hopper and the interior of said conduit, each of said side Walls having an opening for the discharge of lading therethrough by gravity, a door hinged to said enclosure adjacent the upper Side of each last mentioned opening to occupy an inclined position for closing such opening and swingable downwardly to an open position, each door in closed position deiining a part of the respective opening between each apex and said conduit, means providing an air inlet opening to siad conduit, and means providing an air and lading exhaust opening from said conduit.

4. A pneumatically unloadable hopper structure for a railway car or the like comprising, in combination, a four-walled enclosure having downwardly and inwardly sloping spaced apart side walls joined by spaced apart end walls, a floor extending between said end walls and forming the bottom of a conduit the upper portion of which is formed by an inverted V-shaped hood the sides of which with the respective side walls form a pair of V-shaped hoppers with openings at the apex between each V-shaped hopper and the interior of said conduit, the sides of said door extending downwardly underneath the lower portions of said sides of said V-shaped hood and therebeyond and deiining therewith portions of said openings, each of said side walls having an opening for the discharge of lading therethrough by gravity, a door hinged to said enclosure adjacent the upper side of each last mentioned opening to occupy an inclined position in engagement with the respective edge of said v,door for closing such opening and swing- V able `downwardly to Van 'pen'positio'm the inner surfaceV offeaeh door-in closed vpositiontbeing spaced fromitlie lower, edge of the'. respective side Vof said Iv' V-Sliapedf Vho'o'dV and deninganotlier partV of @the respective opening between each apex and said conduit, means providing an airfinletopeningto saidY conduit, and means providing aniair and lading'exhaust opening fromsaid conduitlY v5. lA pneumatically' unloadable Yhopper structure for a railway canV or the like comprising, in combination, wall meansproviding a hopper having a W-shaped Across sectionand thereby providing two V-shaped portions, fioor means joining the apices of the All-shaped portions ofY said hopper and forming with the juxtaposed'inn'er walls thereofY a conduit the interior of which is in cornmunication withthe kinteriors of s aid V-'shaped portions, the opter walls of said Yhopper Yeach having an 'opening form-.falteV discharge of `ladingYtherethrough by,v gravity, a" door `lclosingeach outer wall opening movably mounted on said hoppen-meansvproviding any air inlet to said conduit, and means providing an air and lading exhaust opening from said conduit.

6. In a load containing hopper adapted to selectively discharge lading pneumatically or by gravity,Y in combination, a four-sided fran/ie mounted on the lower portion of said hopper, a door hinged along its upper edge on each of two opposite sides of said frame rand swingable toward the other door to an inclined closed position,lthe edges of said doors furthest` removed'from their hinge axes in closed position being spaced apart, a oor member extending between the other two sides of said frame and bridging the space between said edges of said doors when closed, a ridge shaped member extending between Vsaid other two sides of said frame centrally above said oor member and forming therewith a conduit between said other two sides, the outer sides of said ridge shaped member directing lading to the lower portions of said doors, Ithe lowerV margins of said Sides or" saidridge shaped member being spaced from said doors Vand said iioor member whereby lading can ow into said conduit, means providing an air inlet opening into said cond-uit through one of said other sides of v said frame, and means providing an air and lading exhaust openingrfrom said conduit through the other of said other sides of said frame.

7. Tlhe invention, as set forth in claim 6, wherein the door member is of generally arch shape and the longitudinal edge portions thereof are substantially normal to theV plane of the respective door in the thereof.

8,-The invention, as set forth in claim 7, wherein an operating shaft is journaled on the other sides of the frame underneath the floor member, and operating linkage underneath said oor member interconnects the doors and said operating shaft. Y

'Y 9. The invention, as set forth in claim 8, wherein operating means for rotating the shaft to move the doors closed position S between open and closed positions is mounted onrsaid shaft exterior-ly of theI frame. Y Y Y 10. In a load containing hopper car, in combination, a four-walledV frarne formed by longitudinally extending side walls and transversely extending interconnecting Vend walls, an inverted JY-shaped ridge extending between said end walls intermediate said side walls, eachY side wall having an opening forthe discharge of lading therethronghtby gravity, a door hinged to each side Wall for closing the opening therein, each door in closed position forming one side of a V-shaped hopper the other side of which is formed by the respective Vwall of said V-shaped ridge and opening to discharge lading within the confines of saidrframe; and mechanism for operating said doors including a shaft rotatably mounted on said end walls underneath said ridge, 4toggle locking linkage interconnecting said doors and said shaft, and an operating head Y on one endrof said shaft outside of said frame for receiving` a removable operating bar, said operating head having two sets of radially extending operating bar receiving pockets with the walls forming one set of pockets'being inclined lin one direction andthe walls forming 'the other set of pockets being inclinedin the opposite direction to receive the operating bar for rotating said shaft in one Vdirection or the other.

' 11;In a load containing hopper car, in combination, a four-walled frame formedv by longitudinally: extending side walls and `transversely extending interconnecting end walls, an inverted V-shaped ridge extending between said end walls intermediate said Vside walls, each sidewall having an opening for the discharge of lading therethrough' by gravity, a door hinged to each side wall for closingthe opening therein, each door in closed position forming one side of a V-Vshaped hopper the othersid'e of which` is formed bythe respective wall of said V- shaped ridge andvopening to discharge lading within the contines of said frame; mechanism for operating said' doors including a shaft rotatably mounted on said end walls un- ,derneathfsaidridge toggle locking linkage interconnecting said doors and said shaftLand an operating head on one Aend `of said shaft outside of said frame for receiving a removable operating bar; a radially extending lug on said shaft, yand a lockingN dog pivotally mounted on'said frame and engaging said lug when said doors are closed for holding them closed.

`References Cited in the tile ofrths patent UNITED STATES PATENTS 

